- All right.
So welcome to another episode
of our Maple Webinar Series.
And this is an ongoing series.
We did quite a few in 2020,
and this is our 2021 series.
Tonight, I'm gonna be talking about
Sugarbush Inventory Methods.
And the funding for this work
and in this whole series
is through USDA AMS
Acer Development Grant.
So we thank them for their support.
Like I said, we have more webinars to come.
Tonight, we're talking about
sugarbush Inventory.
In two weeks, we have Chris Lindgren
talking about sap-only enterprises,
if you're really focusing in
on the sap production
and less on the syrup production
aspect of maple.
Then we get into some binding contracts
and legal Agreements.
On October 13th, we have Tony D'Amato
talking about maple forests and carbon,
forest carbon,
which is an interesting topic.
And then we have forest land taxes
and tax abatement programs
at the end of October.
And we're probably
gonna be adding some more dates
that has not been firmed up yet,
but a good slew of topics to come.
So assuming there's no other issues
or people have any problems technically,
please just put those in the chat,
and we will get right to it.
Otherwise, we're gonna get started.
Like all good presentations,
gotta start with a little bit of a background
or introduction.
So the question is what is an inventory?
And this is not unique to forestry,
but in the context of this presentation,
it's a way of measuring and recording
something of interest.
We're talking about taps primarily,
although we'll be talking
about maple trees in general.
But you could easily have an inventory
of all the wetlands on your property,
or you could have an inventory
of all the interesting archeological sites
in or around your area.
You could have an inventory of all the culverts.
That's just a systematic way of measuring
something of interest.
Taking stock of what you have currently
is really important
for planning future activity.
So it's really important to have good ideas
and data on what you have.
And that's really the only way
to go forward with a good plan.
Probably not a surprise to hear that
an inventory often involves
some sort of estimation.
In other words, we're taking a small sample
and trying to use that data
to represent the larger property
or the larger region
or whatever you're inventorying.
Time and money,
there's just no way you can measure everything
once you get beyond a certain scale.
Along those lines, time and money,
you can certainly do
what we're talking about tonight
do it yourself,
do a little DIY inventory.
You could also hire a professional forester.
And much like
putting the siding on a house
or doing some concrete work,
you could probably do it yourself.
Sometimes it might take more time
and more money than you thought
and hiring a professional
is often well worth the money.
So consider a professional forester
who's trained in this type of work.
Why you would do it,
we've already talked about
a few of the reasons why.
Another way is just a basic engagement
with your property.
If you're accustomed
to really just walking around
a certain part of your property,
doing a systematic sample
of your entire property
allows you to see
your property from a different perspective,
it allows you to engage differently
with your whole parcel.
From a business side,
having a good inventory
of what you have for tappable trees
is really important for estimating
tubing installation costs.
It's also important,
if you're looking at a potential property,
say you have excess capacity in the sugar house
and you're interested in
a new property to lease or to buy.
You wanna have a good idea of what you have
for tappable trees there
to get quotes on materials
from tubing manufacturers.
If you're hiring a tubing installer,
you really wanna have a good, accurate number
of what that's gonna be.
I've heard certainly plenty of stories
of people saying,
"Ah, I think I've got about a thousand taps
maybe in these woods,"
when they actually get
into the business of going out there
and starting to lay things out,
sometimes it's 2,000,
sometimes it's more.
There's time and expense associated with that.
Sometimes pricing is better if you
hit certain thresholds
so keep in mind that
beyond just knowing how many taps you have,
it's important in terms
of cost of installation of tubing.
It's also important to understand
the general health of trees,
what you have for regeneration,
and, really, what the general
average diameters are in your woods.
So we'll talk a little bit about why that's important.
The health and regeneration,
typically, if you were just trying to figure out
how many taps you had,
you may not record that.
A forester may use that
in terms of a larger forest inventory.
It really depends on what your goals are
and what kind of information
you're looking to collect.
The simplest would be just a simple tap count.
How many trees are there
that are of tappable size right now
compared to maybe a more complete
or intense inventory
that would involve not just tappable trees,
but site quality, soils,
and lots of other aspects.
It's also important to know,
what's the state of the forest?
Are you a very young stand
that's really just becoming
a small pole size.
Is it intermediate?
Is it more of the old growth?
Has it had very little management over time?
Was there a large harvest recently?
All these things can be important
as you're planning a future tubing system
or expanding an existing one.
So again, this would be
issues that would come up
if you were hiring a forester
to do a full forest inventory,
or if you were looking to do it yourself,
information you'd wanna record
as you're going through
checking on the number of taps you had.
You'd also wanna be including something about
what's the structure,
the age of the stands you're in.
And why does tree size matter?
Well, we know from previous research,
not just at UVM but elsewhere,
that the size of the tree really matters
in terms of how much sap you get.
And that's a fairly linear,
although it's not perfectly linear, relationship.
Larger trees will produce more sap.
And I've also talked with sugar makers who
at first estimated they had say 10,000 taps,
but when you actually went out
and looked at the inventory data
and looked at the trees they were tapping,
the abundance of small trees being tapped
really meant that they were overestimating
how much they could get.
And this can have a real impact
if you're working with a lender
to get money to do this layout
and your yields are based on
a certain amount of sap production per year,
if you're calling every tap,
estimating it's gonna have a certain yield,
if some of those taps
or a good proportion of those taps
are in small trees,
you are probably never gonna hit that estimate.
And within the forest,
not all stands are the same.
Some stands have a higher proportion of small trees,
and some of them are
it's a little bit heavier to larger trees.
So knowing that distribution of diameters
is really important.
And this is a classic inventory technique
that is used in forestry.
If you're growing trees
for timber production,
foresters need to know what diameter classes
have how many trees.
So this is really helpful
in terms of yield as well.
We are currently working
on an online calculator
that would allow you to enter
some of this data by diameter
and you'd get some estimate
based on how many 10-inch trees
versus how many 20-inch trees, and so on,
how much sap you could
realistically expect to produce.
Another interesting difference in inventory
is the distinction between plots and points.
And we're gonna spend a lot of time
a little bit later on in this talk
teasing out the differences
between plots and points.
But the important thing to remember is
the number of sampling places,
be they plots or points,
is really gonna depend a lot of time
on how variable those stands are.
If you have a perfect uniform stand,
they're all the same size,
you really don't need
to take as many points or plots
as you would if there's a lot of variability
between different stands.
So we'll talk about that a little bit.
If you were to establish permanent plots,
that can also help you in terms of
understanding if any forest management activities
you are doing
are having the desired effect.
Forest management plans often will
suggest a certain amount of management over time
that might involve vegetation management,
removing trees, thinning.
If you have permanent plots,
it's a good way of knowing if those
prescriptions are having the desired effect.
So one sort of rule of thumb
is looking for an inch of diameter growth
in 10 years.
That's good growth.
It's not fantastic growth,
but it's a good thing to shoot for.
And it's also important to know
how many small trees,
trees that are too small to be tapped,
are sort of in the pipeline.
How many are gonna be available to tap
in maybe the next round of retubing.
So if you replace your laterals
on a 15-year interval
and you have some trees
that are in that small seven-inch,
eight-inch size class,
if you know that they're coming,
it might be a good way or a good tool
for deciding when you're gonna retube an area.
Also understanding the density of taps
in certain parts of your property.
It might identify areas where it's
really just not worth it to put in
a conductor system
or even just a main line and laterals
because the tap density just aren't worthwhile.
So on the right here, you see a map,
just kind of a heat map in a way.
This was produced by a company that was
marketing a large property.
This property was 2300 acres.
They divided it up into four stands.
And over those four stands,
they took 425 inventory plots.
So quite a few plots
that would have taken a while to do.
That averages out to be about 5 1/2 acres per plot.
And we'll talk a little bit about
why you may or may not
wanna have that many acres per plot.
Another interesting thing
or something to keep in mind
when you're measuring the taps is if,
some trees have significant defects.
Here's a drawing and an illustration
done by George Buzzell
who was a county forester in Vermont.
And he really wanted to get people's attention
thinking about not just a tree as a tap,
but as almost a tapping shell.
So there's conductive tissue there.
If part of that conductive tissue,
a significant part,
is damaged in some way or unusable,
you really wanna reduce
what the sort of functional DBH
or diameter of that tree is.
So this is the kind of detail
that could be included
if you have a large proportion of trees
that have significant decay
or they're damaged,
that would also reduce
the sort of the functional
of the actual number of taps
or the size of those trees that you would tap.
Just another example, a sugar maple borer
is something that could take
a significant part of the tree's conductive tissue
sort of off the table.
So if you had a stand perhaps
that had a really significant outbreak
of something like sugar maple borer
or something else that
impacted the conductive tissue,
you'd wanna be able to
capture some of that information
in your inventory.
Another interesting reason
why you would wanna do an inventory
is to see where the tubing system would be.
Going back to that slide with the heat map,
some areas have more dense
collection of tappable trees
so you might,
if there obvious patterns
to where those trees are,
that's gonna influence
where you're gonna put your conductor systems
where you're gonna put your main lines.
This process will also allow you
to get a better idea
of what the road system is.
There might be some legacy roads
that were put in a long time ago,
even before your ownership perhaps.
Legacy roads often get a bad rap
because they weren't necessarily put in
with water quality
and long-term use in mind.
So if it's an old skid road that
essentially just went right down the slope
and has perpetual issues with erosion,
those are the kind of roads
that could be improved,
or really even just put to bed and abandoned
and in exchange for something that maybe
is easier to travel on,
less prone to erosion.
All these things will come up
when you're doing an inventory
and checking the entire property.
And in case my abstract drawing,
is throwing you off a little bit.
This sort of polygon,
is meant to illustrate,
just a generic forested property
and hopefully those green puffy things
you can identify as trees
and the blue squiggly lines would be
theoretically where a main line might be set up.
When you are collecting
this data based on stands,
you're gonna find a very
variable amount of taps per acre,
and there are pros and cons.
Of course,
a lot of folks might think that
the highest number of taps per acre
is always the goal.
But the issue with that is that
trees are plants,
and they're limited by sunlight,
water and nutrients,
but sunlight is a huge limiting factor.
So when you have too many trees in one area,
they're not optimizing their growth.
And so you would potentially run out of tappable wood.
You are stunting the growth
and we know from previous research
that smaller trees typically will have less sap
on a per year basis.
So remember that it's not just maximizing
the number of taps per acre,
it's maximizing the yield per acre
and also the growth over the long term.
There's a huge range.
You can have sugarbush stands
that have less than 20 taps per acre.
You can have that have more than a hundred
and everything in between.
Generally speaking,
50 taps per acre is considered good.
If you drop below that 20 per acre,
it's really kind of considered not ideal.
It's not enough sap production
given that growing space.
So it could be that it's
not an ideal maple site.
It could be that past management has removed,
the tappable trees.
And it's really in a regrowth phase.
There's a lot of reasons why you might not get
too many taps per acre.
The old model for sugarbush management,
the really, really large decadent,
large crown, widely spaced,
almost open grown trees.
There are still sugar bushes that fit that model.
It really was more of a function
of how sap was collected,
gravity collection buckets,
eating access to the understory
for sap collection.
Big trees, big crowns
definitely produced more sap
and generally sweeter sap,
but it probably does not maximize
your yield per acre
to have that as your goal.
The other issue
with such few number of trees per acre
is the replacement,
the lack of regeneration
or lack of ingrowth of small trees.
So that's something to also consider.
Of course, mapping is really important.
Whenever you're doing any sort of inventory,
you wanna make sure that you know,
the property that you are using
either it's your ownership
or it's the property that you're leasing.
It seems kind of simple to say,
but you really do wanna make sure
that the property boundaries are known.
Here's just a quick screenshot
of some parcel data,
also known as the tax map data.
These are not surveys,
so they don't represent
a careful survey of the property
they give you an idea
of the general shape of a property.
And there's a lot of great information.
Seems like every year, there's more and more
free mapping information out there,
free GPS tools.
Our phones are as powerful
as really any GPS you could really need
for this type of work.
So we can't go into all the detail
about what's available,
but just know that
everything from Google maps to Avenza,
which is helpful because it's offline,
you could download the maps
and use your phone's GPS.
A lot of towns have
this municipal parcel data available.
And it can be helpful.
You can zoom in,
although I don't know if anyone
would recognize the shape,
but this is the Proctor Maple
Research Center property
that I've zoomed into.
And you can zoom in even more.
That's the lab on the right
and the sugar house on the left,
and this is all free.
This is something,
you can play around with at home,
and get a sense of
if it's not your property,
if it's a property you're thinking about leasing,
get a better sense of where the roads are,
where things are at,
is this really gonna be worth my time
before you even invest in doing an inventory.
So let's just assume that you have a property,
a sugarbush,
and you wanna do some inventory.
So you have some choices to make.
First of all,
the sugarbush is part of a forested property
so there are gonna be trees involved.
It's either gonna be owned by the operator,
or you're gonna lease it
and have an agreement with the landowner.
I will put a plugin
for our sugarbush lease guide and a checklist
that can work through the process of developing,
a sugarbush lease,
negotiating a price.
All that information
is available on maplemanager.org.
We've worked with attorneys
so it's a good solid document to use
when you're negotiating with a landowner,
if you're gonna be leasing.
A lot of sugarbushes
are leased on a handshake
and that's great.
There's a tremendous tradition of that.
Unfortunately, they don't always work out
and for the protection of the land owner
and the operator
and all the investments there,
it's a good idea to have something in writing.
So consider looking at those resources
on maplemanager.org.
Larger properties will often be enrolled
in some sort of tax abatement program.
In Vermont it's the Use Value Appraisal
or Current Use program.
Other states have similar programs.
A lot of times,
part of the requirement
is that there's active management
that's based on a forest management plan
that a professional forester has written,
or at least signed off on.
So if that property is yours,
you already have a forest management plan.
You often will probably already
have this information about the property
and the stands.
And in case you don't,
you wanna make sure you know,
what the property boundary is.
If there's some evidence,
but it hasn't been painted recently
in the property boundary,
make sure you know the rules in your state
about who can and who cannot
refresh paint blazes.
In some states, foresters can do it
and other states, they can't,
it has to be done by a professional surveyor.
So you really wanna make sure you know,
what the property extent is
before you start measuring trees
for potentially tapping.
The other important thing to do
is to break the property up into stands.
And stands are really just areas
of similar distribution of trees.
So you might have a stand,
like say that has mostly small trees.
Maybe it was most recently a farm field
and has been abandoned some time ago,
trees stopped being mowed,
trees grew in,
and it's progressing towards
a later successional
or shade tolerant type species.
You might have another stand
that has been in forestry for a long time.
It's really, well-managed,
it's really been maximizing the growth.
Those two stands are gonna look quite different,
and it's often a good strategy
to divide those into different parcels
so you can understand what's there
and manage them accordingly.
There's no set rule
for how many acres you would have
to make a stand.
It's probably on the order of several acres
there'll be a minimum for a stand.
You wouldn't wanna have a stand that's one acre.
Maybe 10 acres, maybe 20.
It really depends on the larger size of the property.
And then how much variability there is,
how many different types of features are there
and what the characteristics
of the trees are in the stand.
So that 2300 acre property
I showed you earlier,
I think that had four stands.
So that gives you a sense of,
you don't have to have a million stands
just because it's a really large property.
They can be fairly large.
And they're generally based on site quality,
hydrology in some ways,
and structure,
it can be done on structure of the trees.
So let's talk a little bit about
what types of inventories you might do.
The first off is the a hundred percent inventory.
That's measuring every single tree.
And you might imagine
this would take the longest.
It's not the most practical.
And definitely not practical
when you get above a couple of acres,
it's just gonna take too long.
So if you're on the hobby side of things,
I think that's certainly a possibility,
but once you get to be
even just a little bit larger
it's gonna be impractical
to measure all those trees.
The next type of sampling
is called plot sampling,
and that's essentially
envisioning a circle of a known size
and distributing those circles
across the stand and across the property
and taking a measurement
within that plot.
And then multiplying by whatever
size plot you used.
So here I gave you three examples
of different plot sizes.
A fifth acre would have a radius of 52.6 feet,
a 10th of an acre would be 37.2 feet,
and a 20th of an acre would be 26.4 feet.
So you can imagine
putting a stick in the ground,
maybe hanging a piece of flag in there
that would be the center of the circle.
And then you would use a measuring tape
or some other way
of accurately measuring the distance
to the 10th of a foot out
and swinging that tape
all the way around in a circle.
The extent of that circle would represent
everything you wanted to count.
So in that case of purely a tap count,
you would measure every tappable tree
within that plot.
And you would repeat that multiple times
throughout the stand
and throughout the property.
And you would multiply that by whatever factor.
So if you took fifth acre plots,
you'd measure every tree in that plot,
multiply that answer by five,
and then you would divide
by the number of plots that you did.
Same thing for a 10th of an acre.
If we measured every single tree
in that 10th acre plot,
then we would multiply that by 10.
And we would get an estimate of how many trees
or taps per acre there were.
Plot sampling is also called
the fixed radius plot.
Typically,
we'd be looking at somewhere between
one plot for every four or five acres.
If you sample more intensively,
you might do three to four acres.
It just means you're gonna be
getting more detailed data.
It'll take more time
if you're paying a forester
or someone trained to do this,
it'll just cost more.
But the idea being that
the larger number of acres for each plot,
you're gonna lose some detail,
but you'll still have a good sense,
of what's happening and how many taps you have.
It's kind of all over the place,
as far as how much
a forester might charge you.
I would think,
again, it depends on the property,
access, all those things,
but it might be
$3 an acre to do plots.
You really would have to talk
to the individual consulting forester
and see what they would estimate.
And going back to the idea
of establishment of permanent plots.
This is another way where
you could put these plots in.
You could actually number those trees
and over time you could keep going back
to those trees
and remeasuring their diameters,
and you would get a sense
of how growth rates are.
And if you combine that
with some of the information
out of the Proctor Center,
in terms of growth rates and sustainability,
you could get a really good sense of
is the tapping intensity that you're practicing
sustainable over the longterm?
Or are you gonna start running
into an issue of hitting non-conductive wood
and losing sap production?
Another, the third type of sampling
would be what's called point sampling
or variable radius sampling.
And this is when you establish points
similar to a plot sample,
but instead of measuring a diameter,
you use a tool to sample
and trees are counted based on their diameter
and the distance from the point
that you established.
So we'll talk about the tools needed
to do that sampling,
but just understand that
you're not measuring a diameter of a circle
in this scenario,
you're just navigating to the points
that you've decided to have
for your sample points.
You're using your tool to measure the trees,
to see whether or not they are
to be counted or not.
And you're moving on.
It's fast, much faster than plot sampling,
and they can be accurate
assuming that people use the correct tools,
and know how to do it.
There is some helpful information available.
If you want more,
I can help you with it.
We'll talk a little bit about how you use the tools,
but it is a little bit more,
than the time allows tonight to train you,
on how to do this type of sampling.
What's really important
and this is true of point sampling
or plot sampling
is that these places, these points
need to be located without bias or randomly.
And by that, I mean,
if you always put your points
on that nice woods road
that you always like to walk down,
you're gonna get a good sample
of what the trees are
around that nice wood road
that you like to walk down,
but it may not be the most representative sample
of the trees you have in your woods.
And as much as we think we can control our bias,
it's difficult.
And so using,
some of the free software that's available,
to randomly put points down
on your property map,
that can help you eliminate some of those biases,
even just walking uphill or downhill
can influence where you put your point.
So just one last thing to say is
if the goal is to get a real accurate count
of how many trees you have to tap,
it's important to make sure
that you're sampling the entire property,
not just the areas that are easy to walk through
or are easy to get to.
That's all I'll say about that.
Like I said, you can put in more plots,
but it will take more time or cost more
if you're hiring someone to do that work.
Here's another way of envisioning
that variable radius plot concept.
So let's say that red X
is the point center
and you're standing there
and you're measuring the trees
in that location.
You're gonna use one of the tools
that I'm gonna describe in a minute.
And you will look around that whole,
all the way in 360 degrees around that point.
And you will measure to see
if the trees are tallied or not,
and they will become
more likely to be tallied the larger they are.
So larger trees are more likely to be counted,
but that just means that,
it's how the tools are designed.
I'll talk about that just a second.
To be consistent
it's really important to start at the same point.
So you wanna start at due North
and work your way around
the convention is to work clockwise
around in a circle.
You don't have to measure out the plot
in these point samples,
but you do need to make sure you're not
counting the same tree over and over again,
or multiple times.
So use some sort of landmark
or some sort of identifiers
so that you know you've come back around,
to the starting point
when you're working your way around in a circle.
The important thing is that you're standing
right above that point center.
You're not walking out to those trees.
You wanna make sure
all those trees you're measuring
are happening right from that plot center.
I will say the last type of inventory
is sort of a quick and dirty,
and that is just to visualize a football field.
So a football field
is just about an acre in size.
Most woods you can't see
the equivalent of a football field,
but you can probably estimate how close.
And that would be another way to do it
real quick and dirty, jump in there,
decide whether or not you can see roughly
half a football field,
or maybe a little more,
count the trees
and that'll get you on your way.
Like all quick and dirty things
they'll get you a little bit of information,
but it's not gonna be the most accurate
by any means.
And it could cause you to make some choices
in terms of buying materials
or hiring installers
or any number of things
that you may wish you had done
a little bit more high quality inventory.
So what tools are we gonna use?
We have a couple of forestry tools,
that are pretty common,
a diameter tape,
or a Biltmore stick.
These are ways of measuring diameter.
You have an angle gauge or a prism.
These are ways of determining
whether or not tree is to be tallied or not.
A measuring tape.
This would be like a a hundred foot
or a hundred meter tape.
That's what you would use to determine,
if you're doing plot sampling,
how far is that radius?
How big is the plot?
Am I gonna do a fifth of an acre?
Am I gonna do a 20th of an acre,
whatever that is.
Map and compass.
Still important even the digital age,
it's really important to have
a sense of where you're at,
how to navigate to these data points
if your phone isn't available or not working.
And then a data sheet.
Got to have a way of inventorying that data.
A Biltmore stick is very simple.
It's a wooden stick
that looks kinda like a yard stick.
It's designed with graduations
along one side to measure diameter.
You line up one edge of the Biltmore stick
on one edge of the tree.
You hold it a set distance away from your eye,
and you look along the other edge
of the diameter of the tree.
And you see where that tree
edge of the stem intersects with
the diameter markings on the tree.
They're in graduations of
one foot or two foot,
sorry, one inch or two inch,
and they're not especially precise,
but it does give you a ballpark
number for diameter
and probably precise enough,
for the purposes of measuring
number of taps per tree.
A couple of things to keep in mind.
You always wanna measure
on the high side of the tree.
High side of the base of the stumps.
So if you're on sloped land,
you're gonna wanna make sure
that you're on that high side,
not on the bottom or on the side.
And you always wanna measure it
four and a half feet above the ground.
That's the forestry convention
for diameter at breast height.
And this just allows for
removing mistakes from tree to tree.
So a more precise measure
would be a diameter tape.
Here's one that's divided up.
On one side it has regular length measurements
and the other, it has diameter.
And the way it works is it takes circumference
and it does the math
and converts it to diameter.
So here's a diameter tape measuring,
in this case a cookie of a sugar maple tree.
And it's almost 11.9 inches,
but it's just a little under 11.9
between 11.8 and 11.9.
If you can see the bottom part of the tape,
there's a line and I'm lining up my eye
with where that bottom line
and the graduations above.
And this is divided up into tenths.
If you're using a D-tape,
make sure the tape is level,
parallel with the ground
or perpendicular to the stem.
It's not up or down in some way and not twisted
because that would impact the measurements.
So that's measuring diameter.
You also have point sampling tools
and plot sampling tools.
So an angle gauge is an inexpensive way
of point sampling.
And you basically look through that
oddly shaped opening in the angle gauge,
and you look to see whether or not,
the tree in question fills that space,
that little void or not.
And there's a couple of different,
there's a five, a 10, a 20,
and actually even a 40 factor.
Let's go to the very top and that's the five.
So if a tree totally fills that slot,
that's the width by the five
then the tree would be counted.
If it doesn't fill that,
if you can see daylight
on either side of the tree within that slot,
then it isn't counted
and you rotate this around plot center
or point center,
and that chain is meant
to set the distance away from your eye.
So you would hold that either up to your mouth
or some people would actually put it in their mouth,
but it's probably not tasty
to chomp on that.
But you wanna make sure
that distance is kept constant
as you're rotating around the plot.
And you're counting
all the trees that are filling that void.
A cheap and easy way
instead of using the angle gauge
is using a penny.
That's similar to the 10 factor
that was on that angle gauge.
It's not exactly the same.
So it would actually tell you
slightly fewer trees.
So you might do an under count.
And that illustration below
you can see that kind of penny,
the view from your eye
of whether or not that penny
totally covers the tree diameter or not.
And if it is equal to that diameter or greater
then you would count it.
And if the penny is larger than the stem,
you would not count it.
And you would repeat this
for all the number of points
that you had decided
was appropriate for your stand.
A more expensive,
but more precise
way of doing point sampling
is using a wedge prism.
And this is a well engineered,
carefully engineered wedge of glass
that you look through
and the angle of that glass,
it has a set angle,
and that does a certain amount of offset.
It makes the view through that prism,
slightly offset from what you see
above and below the prism.
And depending on if the offset overlaps
or is completely exposed
would be whether or not
you tally the tree or not.
That's a little abstract to say in words,
this is an illustration
of what it would look like.
The tree on the left in this illustration
would be out because it doesn't overlap
the tree in the middle clearly overlaps
and would be counted as a tree.
And the tree on the right
is right on the borderline.
It's really hard to tell.
There's different conventions
about what to do in this case.
Some conventions would say
treat every other one,
count every other one.
So you just have to keep track
of whether or not
the last one you counted in.
And then the next time you have
a borderline tree,
you would not count it.
So if you're taking that extra step
of understanding,
the diameter distribution of trees,
you would go out to all the counted trees,
the trees like in the middle
that are clearly overlapping,
and you would measure the diameter
and you would record that.
One other thing, actually, we can go to this.
In reality, this is what it looks like
when you're looking through a prism,
you can see the center of the stem is offset,
but it is clearly overlapping above and below.
So this would be a tree I would count.
Remember when you're doing point sampling,
it's really important that you establish
that point center right away.
Put a stick in the ground,
put some flagging there,
something that's not gonna move
because even just a little bit of movement,
side to side or front and back
can make the difference of whether or not
a tree is counted or not.
And that the same is true for a plot.
You don't wanna be moving plot center around
because just a little bit of difference
can impact whether or not
a tree is counted.
And it'll just make your data inaccurate.
Data sheet.
Very important.
You wanna record that data.
You can make your own data sheet.
It doesn't have to be complicated.
You do wanna make sure,
you're keeping a tally
of how many tappable trees.
If you are looking for
potentially getting a loan,
they're gonna wanna know
how many taps per acre there are
on this property,
because that's gonna impact
your ability to produce sap, syrup
and in their mind pay back the loan.
So really important to have good numbers on this.
The stands are important
because you wanna be able to compare,
what stands have the most,
the good density of trees
and which ones are maybe a little thin.
And you also wanna make sure
you write down what the plot size.
If you're doing fixed radius plots,
you wanna make sure you know,
what size plot you are doing
so you can do the math
on estimation of trees or taps per acre.
So here's an example.
You can break it up by diameter class.
In forestry it's a little odd
there would be a range in diameters.
Generally speaking
it's a two inch diameter class.
So if you say a 10 inch tree,
that is 10 inches as the center point
of a two inch diameter class.
And so it could go everywhere
from a nine inch tree to an 11 inch tree
and so on.
Embracing the forestry methods
might be a little confusing.
You could do your own data sheet,
make up your own diameter classes,
however you wanna do it,
but make sure you're having a space
to tally the trees that are in
and knowing what size plot you're using.
If you're using a point sampling
then you can find this information
online as well,
there is a multiplier of some sort of a factor
to estimate how many
based on whatever factor prism you're using.
The prism that are most common
would be a 10 factor prism,
but you would have a multiplier.
So multiplying whatever number of trees
you tallied in that various diameter class,
you would multiply by that factor
and then you would total up
for number of taps per acre.
Developing something consistent,
a data sheet that will work for you
is important.
Make sure that whoever is doing this work,
has thought through,
what stands they're gonna do,
how many points they're gonna do,
how they're gonna navigate to those points.
And that is what I got for you.
So there's a fair amount to cover there,
and hopefully you got something out of it
and I'd be happy to take some questions now.
I can stop sharing
and I will try to give everyone a chance to
- And Mark, this is the other Mark.
I'm just gonna chime in and read one question
off the chat box.
- Sure.
- And then I can start unmuting if you want.
- Okay.
- Question came in a few minutes ago
I think this was right before you went
to some of the point sampling techniques.
What about CIR, Color Infrared Imagery
to determine type and size
for a method of inventory?
- Yeah, that's a good,
that's pretty high-tech.
There is definitely some remote sensing
that can be done to look at species,
obviously would have to be
when the leaves are on.
I am not that familiar with that technology
so I wouldn't be able to estimate.
I think it could probably give you
a good sense broadly of what percentage
in your stand are maple versus not,
but without getting on the ground,
it's hard to do diameters.
And I know LIDAR,
which is also a modern remote sensing technique
has come a long way.
They're not there yet
in terms of measuring diameter
from that far away.
So I would still say that
someone has to be on the ground
measuring those trees.
So I think everyone now,
I think I gave everyone permission to unmute.
So if anyone else has questions,
I'd be happy to happy to take them there.
Or if you wanna contribute,
how you're approaching
inventorying your own property
or issues that you've run into
in terms of measuring trees.
Love to hear it.
- Hi, Mark, it's Jenny from Ontario.
Thanks for the great presentation.
- Hi Jenny.
- Hi.
So I just had a quick question about,
you mentioned earlier that
some trees might not have fully functional DBH,
and that that could also be included
in the inventory.
Do you have any tools or tips
for how to do that?
- Yeah, I mean,
the easiest would be just to estimate.
You look at an individual tree
that has a big area of decay
that's visibly non-conductive,
you would have to make some sort of estimation.
Is it 20% of the tappable area
and just reduce it proportionally.
The individual tools,
we can't see inside the tree
so it would have to be a really visible defect
for you to make that sort of deduction
in terms of a functional diameter.
There's some question about,
what's the maximum capacity of sap flow
through a certain unit of wood.
So like that, for instance,
that sugar maple board that I showed you.
That's a big proportion of the tree circumference
under sort of gravity
sap collection techniques
you would expect
that the reduction would be significant.
But with high vacuum,
we don't really know enough
at this point to say,
would you see as a dramatic reduction?
I think it's safe to estimate
that yes, you would,
and make some sort of reduction.
And I don't want it to suggest
that you do this for every individual tree,
'cause it would take too long.
I guess I'm bringing it up because
if you have a stand
that has a lot of issues with decay
it's worth noting,
it's worth considering
and making some reductions,
but also those might be good candidates to remove
and maybe put the limited sunlight
that's out there,
onto trees that have a better chance
of living over the longterm
and putting on new growth.
- Thank you.
- This is Mark Cannelo.
I'll just remind folks feel free to,
you should be able to unmute yourself
if you go to your permission,
look at the little microphone
and if you're more comfortable
typing into the chat box,
don't hesitate to type in a question there
and I'll be sure to read it
if the other Mark doesn't read it right away.
Mark, I'm just gonna ask one question if I can.
A lot of times coming back to yield,
to sap yield and overall sugar yield
I know we've got a great legacy
of talking about yield per tap.
And what I'm kind of understanding
from this presentation is that
really it's sort of changing the orientation
from a tree basis to an acre basis.
And I'm just curious
if you have any thoughts about when,
as a forester when you hear people
talking about yield per tap,
do you have any thoughts about
the potential or the merits
of people considering their yield
more on an acre basis
rather than on a estimated tap level?
- Yeah, I mean,
it's dynamic because,
at any one given time you might have,
a really high yield per tap,
but over time,
if you're not maximizing
the growth of those trees,
you are probably gonna see that yield go down
because the trees
aren't putting on enough wood
to make up for what's being removed
from tapping.
Both, the wood that's removed
by the tapping process,
but also the non-functional wood
accumulate over time.
I think that the yield per acre
is an interesting idea.
The silviculture,
I would say isn't totally settled.
I think I alluded to it a little bit
when I was talking about that older style
of widely spaced, large crown trees,
but the issue with maximizing the number of,
Oh, I think I talked about it,
maximizing number of taps per acre,
is that you might find yourself
tapping smaller and smaller trees
and not paying attention to tree growth.
I'm not sure if that really answers your question.
Yes per acre is a good way
of approaching things,
but you also have to understand
the underlying patterns or distribution
of what size trees you have
so you don't end up in a scenario where
you've tapped the same trees for years,
and you don't have regeneration
coming to replace them,
or you're at such a low growth rate
that your yields go down and down and down
because you consistently hit
staying non-conductive wood.
I think I saw a note from Nicholas.
Is there a tree health classification,
like the MSCR in Quebec that you use
to inventory the health of the sugarbush?
Nicholas,
I'm not familiar with the MSCR actually,
but in forestry,
there's definitely vigor
and health measurements.
It's not as common
in a sugarbush inventory.
Typically it'll be a pretty simple just
what size tree and is it tappable?
I think much like
Jenny's question about the tapping shell
or how much conductive wood is there to tap
I think it's really
a tap is not a tap is not a tap,
just like a five inch tree
should not be added to the same bucket
as a 15 inch tree.
They just represent different potential
in terms of yield.
So an unhealthy tree,
there should be a way of identifying
and letting the landowner or the producer know
what proportion of their trees
might have compromised health.
But Nicholas,
I don't know how widespread
that type of measurement system is
in sugar bushes.
It depends largely on if it's a property
with a long-term forest management plan,
if that is brought up
in those documents.
Thanks for your question.
- Hey mark, this is Tony here.
I had a question for you.
I'm actually looking at a new property
and I've already done some sampling
with the prism method.
And so I've taken
about a hundred points actually.
And the average captains tap density
I'm getting is quite high,
about 105 to 110 taps an acre.
And it made sense
because there's lots of small trees
and pole what, right?
- Right.
- So the forest is just ready to start tapping,
but it doesn't have many mature trees.
Now trying to take that.
And then, so if we look at the,
what you were alluding to,
yield per diameter.
Yeah, I can take the 110
and just multiply it by,
0.25 gallons of tap to get a yield.
But, if there were big healthy trees,
I'd get more sap per tap.
So I'm trying to co-relate,
a smaller diameter size class forest
with let's say the average expected yield.
So all I'd have to do is like,
when I take that curve that you showed
in one of your first,
the correlation between sap per tap
and the diameter,
if I take those numbers,
I get ridiculously high yield
because they're like,
I think it was a hundred gallons per tap,
it's just out of the,
it's like ideal conditions.
So I'm trying to figure out
how can I make a factor
that would account for the fact
that my trees are smaller diameter.
- Right, right.
Well, and that's a good observation
that those numbers are based on ideal conditions.
I would say that,
you could discount by a certain percentage,
take the average diameter for that stand.
If you're measuring diameter,
if you know how many in each size class,
you could discount by a certain percent.
And it might be in the 5% per inch
diameter range.
We haven't really worked out
the relationship super strongly,
but I'm guessing it's in the five to 7%
per inch diameter range.
As you go larger,
you're gonna get progressively more sap.
So many factors could influence that,
vacuum intensity at the taphole,
sanitation.
All those things are gonna influence that.
But the relationship like in that graph
that I put on earlier
shows it's fairly linear,
but it's in that five to 7%,
per inch DBH range.
And then the other issue is, management wise,
if you have a lot of small trees,
the temptation is to maybe remove some
and try to pick the winners
that you think are gonna be
the crop trees of the future,
depending on,
again, without seeing the stand
or seeing the stand data,
it's hard to say,
but it can be tempting to take out too much.
There are a lot of things that can contribute,
to take small trees out of the equation,
either natural dynamics or what have you.
So it's good to flag some,
ones that look like good winners,
but when they're in that
really small pole size,
it might be a little small
to start doing any real
pre-commercial type work
to try to focus on the winners.
Stem form is probably the biggest thing
that you would use to decide
whether or not to take a tree out.
Let's see, Dave Matt says,
"Knowing that the goal is to have
at least 25% non maple in the stand,
should the inventory include non maple stems
to give one an idea of species composition
and total number of trees per acre?"
Yeah, that's a great point, Dave,
and it's sort of points out that
if you're just looking at taps,
you're ignoring,
what else is growing there.
Obviously in a stand
that's naturally heavy to maple,
it's gonna be mostly maple,
but we know that there's lots of other species
in the woods.
So it would be a good idea
to have a more comprehensive inventory
and one that would align with other goals
besides tapping
like long-term forest management goals.
And keeping that diversity especially,
it's a requirement.
If you're a certified organic,
you would wanna make sure that you are
reaching that threshold.
Good question.
Any other questions?
Appreciate everyone's time and attention
and their questions.
There's a fair amount of cover.
There are lots of resources,
if you wanna develop your own inventory method,
to get a little better handle
on how to use the angle gauge,
there are definitely some tutorials
really rooted more
in the forestry side of things
but if you have questions in the future,
don't hesitate to reach out to me,
for help finding those resources.
I would like to say that,
we're continuing this webinar series.
In two weeks, we have another one coming up
and that's on sap-only Enterprises.
I don't have the list in front of me,
but I can pull that right up.
- I could pull it up if you don't mind.
This is Mark and I just wanna thank
Mark Isselhardt for a great presentation.
Always great content
and always presented well.
The outlook as people start to get off,
sap-only Enterprises on September 15th
with Chris Lindgren.
The next webinar after that
is Wednesday, September 29th.
That'll be me having a discussion
about binding contracts
and binding legal agreements.
Then on October 13th,
we've got Dr. Tony, D'Amato
talking about maple forests and carbon,
and then the initial calendar ends up
on October 27th
with the presentation I'll be giving
with attorney Jess Phelps
on Northeast forest land tax programs
and tax abatement.
Sounds like Mark has given
a little bit of a teaser
that there may be some ad-on sessions
later on in the fall.
So we'll be watching in earnest
as those calendar dates become available.
- Great.
Well, thanks everyone for tuning in.
And if you know someone
who missed out on tonight's presentation
or some of the earlier ones in the series,
we post them
on the maplemanager.org website.
And we also have recordings
from last year's series.
So go check that out
for more information.
And with that, I'll say thanks to Mark,
for doing the back of the house stuff.
And we will see you all soon, take care.
- All right, goodnight.